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https://www.readbyqxmd.com/read/28088636/comparison-of-mucoadhesive-and-cohesive-features-of-poly-acrylic-acid-conjugates-respective-their-molecular-mass
#1
Flavia Laffleur, Kathrin Knapp, Wongsakorn Suchaoin, Alexandra Partenhauser, Kesinee Netsomboon, Andreas Bernkop-Schnürch
OBJECTIVES: This study aimed to assess the impact of molecular mass as well as the differences between poly(acrylic acid)-thiol-conjugates (PAA100,250,450 KDa) on their mucoadhesive and cohesive qualities. METHODS: Covalent attachment of cysteine (CYS), cysteamine (CYSM) and L-gluthathione (GSH) to poly(acrylic acid) was achieved by formation of amide bonds between primary amino group of the amino acid (in the case of cysteine and glutathione), respectively the amino group of the aminothiol cysteamine and carboxylic acid group of the polymer...
January 11, 2017: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/28088563/a-novel-fabrication-of-a-high-performance-sio2-graphene-oxide-go-nanohybrids-characterization-of-thermal-properties-of-epoxy-nanocomposites-filled-with-sio2-go-nanohybrids
#2
S Z Haeri, B Ramezanzadeh, M Asghari
In this study it has been aimed to enhance the thermal resistance of epoxy coating through incorporation of SiO2-GO nanohybrids. SiO2-GO nanohybrids were synthesized through one-step sol-gel route using a mixture of Tetraethylorthosilane (TEOS) and 3-Aminopropyl triethoxysilane (APTES) silanes. The SiO2-GO nanohybrids were prepared at various hydrolysis times of 24, 48 and 72h. Then 0.2wt.% of GO and SiO2-GO nanohybrids were separately incorporated into the epoxy coating. Results revealed that amino functionalized SiO2 nanoparticles with particle size around 20-30nm successfully synthesized on the basal plane of GO...
January 5, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28088021/sanguinarine-induced-oxidative-stress-and-apoptosis-like-programmed-cell-death-al-pcd-in-root-meristem-cells-of-allium-cepa
#3
Aneta Żabka, Konrad Winnicki, Justyna Teresa Polit, Janusz Maszewski
A vast number of studies on plant cell systems clearly indicate that various biotic and abiotic stresses give rise to the uncontrolled increase in the level of reactive oxygen species (ROS). Excess concentrations of ROS result in damage to proteins, lipids, carbohydrates, and DNA, which may lead, in consequence, to the apoptotic cell death. The current study investigates the effects of sanguinarine (SAN), a natural alkaloid derived from the roots of Sanguinaria canadensis, on root apical meristem cells of Allium cepa...
January 4, 2017: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/28087593/norovirus-mediated-modification-of-the-translational-landscape-via-virus-and-host-induced-cleavage-of-translation-initiation-factors
#4
Edward Emmott, Frederic Sorgeloos, Sarah L Caddy, Surender Vashist, Stanislav Sosnovtsev, Richard Lloyd, Kate Heesom, Nicolas Locker, Ian Goodfellow
Noroviruses produce viral RNAs lacking a 5' cap structure and instead use a virus-encoded VPg protein covalently linked to viral RNA to interact with translation initiation factors and drive viral protein synthesis. Norovirus infection results in the induction of the innate response leading to interferon stimulated gene (ISG) transcription. However the translation of the induced ISG mRNAs is suppressed. A SILAC-based mass spectrometry approach was employed to analyse changes to protein abundance in both whole cell and m7GTP-enriched samples to demonstrate that diminished host mRNA translation correlates with changes to the composition of the eukaryotic initiation factor complex...
January 13, 2017: Molecular & Cellular Proteomics: MCP
https://www.readbyqxmd.com/read/28087528/engineering-mycobacteria-for-the-production-of-self-assembling-biopolyesters-displaying-mycobacterial-antigens-for-use-as-tuberculosis-vaccine
#5
Jason W Lee, Natalie A Parlane, Bernd H A Rehm, Bryce M Buddle, Axel Heiser
: Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis or Mycobacterium bovis and still remains one of the world's biggest global health burdens. Recently, engineered polyhydroxyalkanoate (PHA) biobeads produced in both E. coli and Lactococcus lactis displaying mycobacterial antigens were found to induce significant cell mediated immune responses in mice. We observed that such PHA beads contained host cell proteins as impurities which we hypothesized to have the potential to induce immunity...
January 13, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28087479/synthesis-and-characterization-of-gold-nanostructured-chorin-e6-for-photodynamic-therapy
#6
L Vieira, M L Castilho, I Ferreira, J Ferreira-Strixino, K C Hewitt, L Raniero
Photodynamic therapy is an alternative treatment for cancer based on cellular uptake of a photosensitizer, illuminated with an appropriate wavelength in the presence of oxygen. A cascade of reactions generates reactive oxygen species leading to cell death. Using carbodiimide chemistry, chlorin e6 (Ce6) was covalently bonded to thiourea, and (via the sulphur end group) to gold nanoparticles (AuNPs), forming the Ce6-AuNP complex. Ce6 absorbs in the range 650-680nm, where the coefficient of biological tissue absorption is low (part of the therapeutic window), which is ideal for biological application...
January 10, 2017: Photodiagnosis and Photodynamic Therapy
https://www.readbyqxmd.com/read/28087399/advances-with-using-crispr-cas-mediated-gene-editing-to-treat-infections-with-hepatitis-b-virus-and-hepatitis-c-virus
#7
REVIEW
Buhle Moyo, Kristie Bloom, Tristan Scott, Abdullah Ely, Patrick Arbuthnot
Chronic infections with hepatitis B and hepatitis C viruses (HBV and HCV) account for the majority of cases of cirrhosis and hepatocellular carcinoma. Current therapies for the infections have limitations and improved efficacy is necessary to prevent complications in carriers of the viruses. In the case of HBV persistence, the replication intermediate comprising covalently closed circular DNA (cccDNA) is particularly problematic. Licensed therapies have little effect on cccDNA and HBV replication relapses following treatment withdrawal...
January 10, 2017: Virus Research
https://www.readbyqxmd.com/read/28087320/poly-adp-ribose-polymerase-activity-and-inhibition-in-cancer
#8
REVIEW
Caleb Dulaney, Samuel Marcrom, Jennifer Stanley, Eddy S Yang
Genomic instability resultant from defective DNA repair mechanisms is a fundamental hallmark of cancer. The poly(ADP-ribose) polymerase (PARP) proteins 1, 2 and 3 catalyze the polymerization of poly(ADP-ribose) and covalent attachment to proteins in a phylogenetically ancient form of protein modification. PARPs play a role in base excision repair, homologous recombination, and non-homologous end joining. The discovery that loss of PARP activity had cytotoxic effects in cells deficient in homologous recombination has sparked a decade of translational research efforts that culminated in the FDA approval of an oral PARP inhibitor for clinical use in patients with ovarian cancer and defective homologous recombination...
January 10, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28087273/chitosan-cross-linked-with-poly-ethylene-glycol-dialdehyde-via-reductive-amination-as-effective-controlled-release-carriers-for-oral-protein-drug-delivery
#9
Zi-Wei Jing, Zhi-Wei Ma, Chen Li, Yi-Yang Jia, Min Luo, Xi-Xi Ma, Si-Yuan Zhou, Bang-Le Zhang
The covalently cross-linked chitosan-poly(ethylene glycol)1540 derivatives have been developed as a controlled release system with potential for the delivery of protein drug. The swelling characteristics of the hydrogels based on these derivatives as the function of different PEG content and the release profiles of a model protein (bovine serum albumin, BSA) from the hydrogels were evaluated in simulated gastric fluid with or without enzyme in order to simulate the gastrointestinal tract conditions. The derivatives cross-linked with difunctional PEG1540-dialdehyde via reductive amination can swell in alkaline pH and remain insoluble in acidic medium...
December 31, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28081016/graphene-as-a-flexible-template-for-controlling-magnetic-interactions-between-metal-atoms
#10
Sungwoo Lee, Dongwook Kim, Alex W Robertson, Euijoon Yoon, Suklyun Hong, Jisoon Ihm, Jaejun Yu, Jamie H Warner, Gun-Do Lee
Metal-doped graphene produces magnetic moments that have potential application in spintronics. Here we use density function theory computational methods to show how the magnetic interaction between metal atoms doped in graphene can be controlled by the degree of flexure in a graphene membrane. Bending graphene by flexing causes the distance between two substitutional Fe atoms covalently bonded in graphene to gradually increase and these results in the magnetic moment disappearing at a critical strain value...
January 12, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28080251/tetrahedral-dna-nanoparticle-vector-for-intracellular-delivery-of-targeted-peptide-nucleic-acid-antisense-agents-to-restore-antibiotic-sensitivity-in-cefotaxime-resistant-escherichia-coli
#11
John Benedict Readman, George Dickson, Nick G Coldham
The bacterial cell wall presents a barrier to the uptake of unmodified synthetic antisense oligonucleotides, such as peptide nucleic acids, and so is one of the greatest obstacles to the development of their use as therapeutic anti-bacterial agents. Cell-penetrating peptides have been covalently attached to antisense agents, to facilitate penetration of the bacterial cell wall and deliver their cargo into the cytoplasm. Although they are an effective vector for antisense oligonucleotides, they are not specific for bacterial cells and can exhibit growth inhibitory properties at higher doses...
January 12, 2017: Nucleic Acid Therapeutics
https://www.readbyqxmd.com/read/28080064/collective-excitations-in-protein-as-a-measure-of-balance-between-its-softness-and-rigidity
#12
Utsab Raj Shrestha, Debsindhu Bhowmik, Kurt William Van Delinder, Eugene Mamontov, Hugh M O'Neill, Qiu Zhang, Ahmet Alatas, Xiang-Qiang Chu
In this article, we elucidate the protein activity from the perspective of protein softness and flexibility by studying the collective phonon-like excitations in a globular protein, human serum albumin (HSA) and taking advantage of the state-of-the-art inelastic X-ray scattering (IXS) technique. Such excitations demonstrate that the protein becomes softer upon thermal denaturation due to disruption of weak non-covalent bonds. On the other hand, no significant change in the local excitations is detected in ligand- (drugs) bound HSA compared to the ligand-free HSA...
January 12, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28080053/lipid-drug-conjugate-for-enhancing-drug-delivery
#13
Danielle Irby, Chengan Du, Feng Li
Lipid-drug conjugates (LDCs) are drug molecules that have been covalently modified with lipids. The conjugation of lipids to drug molecules increases lipophilicity and also changes other properties of drugs. The conjugates demonstrate several advantages including improved oral bioavailability, improved targeting to the lymphatic system, enhanced tumor targeting, and reduced toxicity. Based on the chemical nature of drugs and lipids, various conjugation strategies and chemical linkers can be utilized to synthesize LDCs...
January 12, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28079984/medical-application-of-glycosaminoglycans-a-review
#14
REVIEW
Alexander Köwitsch, Guoying Zhou, Thomas Groth
The characteristic molecular composition of the different glycosaminoglycans (GAG) is related to their role as structural components and regulators of a multitude of functions of proteins, cells and tissues in the human body. Therefore, it is not surprising that GAG are widely used as coating materials for implants, components of 3D-constructs like tissue engineering scaffolds and hydrogels, but also as diagnostic devices like biosensors and in controlled release applications. Beside a physisorption or encapsulation of GAG, these applications often require their chemical modification to allow a stable covalent attachment on surfaces or cross-linking reactions with other molecules...
January 12, 2017: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/28079367/robust-responsive-and-targeted-plga-anticancer-nanomedicines-by-combining-reductively-cleavable-surfactant-and-covalent-hyaluronic-acid-coating
#15
Jintian Wu, Jian Zhang, Chao Deng, Fenghua Meng, Ru Cheng, Zhiyuan Zhong
PLGA-based nanomedicines have enormous potential for targeted cancer therapy. To boost their stability, targetability and intracellular drug release, here we developed novel multifunctional PLGA anticancer nanomedicines by combining a reductively cleavable surfactant (RCS), vitamin E-SS-oligo(methyl diglycol L-glutamate), with covalent hyaluronic acid (HA) coating. Reduction-sensitive HA-coated PLGA nanoparticles (rHPNPs) were obtained with small sizes of 55 - 61 nm and zeta potentials of -26.7 - -28.8 mV at 18...
January 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28079307/coordination-of-krf2-to-a-naked-metal-cation-mg-2
#16
Matic Lozinšek, Hélène P A Mercier, David S Brock, Boris Žemva, Gary J Schrobilgen
Examples of coordination compounds in which KrF2 functions as a ligand are very rare. In contrast, XeF2 provides a rich coordination chemistry with a variety of main-group and transition metal cations. The reactions of Mg(AsF6 )2 and KrF2 in HF or BrF5 solvent have afforded [Mg(KrF2 )4 (AsF6 )2 ] and [Mg(KrF2 )4 (AsF6 )2 ]⋅2 BrF5 , respectively, the first examples of a metal cation ligated by KrF2 . Their X-ray crystal structures and Raman spectra show that the KrF2 ligands and [AsF6 ](-) anions are F-coordinated to a naked Mg(2+) cation...
January 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28079302/molecular-basis-for-covalent-inhibition-of-glyceraldehyde-3-phosphate-dehydrogenase-by-a-2-phenoxy-1-4-naphthoquinone-small-molecule
#17
Stefano Bruno, Elisa Uliassi, Mirko Zaffagnini, Federica Prati, Christian Bergamini, Riccardo Amorati, Gianluca Paredi, Marilena Margiotta, Paola Conti, Maria Paola Costi, Marcel Kaiser, Andrea Cavalli, Romana Fato, Maria Laura Bolognesi
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has recently gained attention as an anti-protozoan and anti-cancer drug target. We have previously identified 2-phenoxy-1,4-naphthoquinone as an inhibitor of both Trypanosoma brucei and human GAPDH. Herein, through multiple chemical, biochemical, and biological studies, and through the design of analogs, we confirmed the formation of a covalent adduct, we clarified the inhibition mechanism and we demonstrated antitrypanosomal, antiplasmodial and cytotoxic activities in cell cultures...
January 12, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28079287/triarylmethane-dyes-for-artificial-repellent-cotton-fibers
#18
Adelina Vallribera, Ana Maria Montagut, Erik Gálvez, Rosa María Sebastián, Alexandr Shafir
Families of new hydrophobic and/or oleophobic triarylmethane dyes possessing long hydrocarbon or polyfluorinated chains have been prepared. When covalently grafted upon cotton fabric, these dyes give rise to a new type of colored superhydrophobic fibers.
January 12, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28078594/exploration-of-fas-s-nitrosylation-by-the-biotin-switch-assay
#19
Ali Bettaieb, Catherine Paul, Stéphanie Plenchette
S-nitrosylation is the covalent attachment of nitric oxide radical to the thiol side chain of cysteine. The death receptor Fas/CD95 can be S-nitrosylated in cancer cell lines by NO donors or iNOS activation. This posttranslational modification (PTM) induces Fas aggregation into lipid rafts and enhances FasL-mediated signaling and apoptosis. In this report, we describe the detection of Fas S-nitrosylation by the most commonly used method, the biotin switch assay (BSA) technique, that allows the detection of this very labile covalent modification in cells or tissues...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28078593/detection-of-s-acylated-cd95-by-acyl-biotin-exchange
#20
Aurelie Rossin, Anne-Odile Hueber
S-acylation is the covalent addition of a fatty acid, most generally palmitate onto cysteine residues of proteins through a labile thioester linkage. The death receptor CD95 is S-palmitoylated and this post-translational modification plays a crucial role on CD95 organization in cellular membranes and thus on CD95-mediated signaling. Here, we describe the nonradioactive detection of CD95 S-acylation by acyl-biotin exchange chemistry in which a biotin is substituted for the CD95-linked fatty acid. This sensitive technique, which depends on the ability of hydroxylamine to specifically cleave the thioester linkage between fatty acids and proteins, relies on three chemical steps: (1) blockage of free thiols of non-modified cysteine residues, (2) hydroxylamine-mediated cleavage of thioester-linked fatty acids to restore free thiols and (3) biotinylation of free thiols with a thiol reactive biotinylation agent...
2017: Methods in Molecular Biology
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